Ignition arrangment for internal combustion engines

ABSTRACT

An ignition arrangement for internal combustion engines in which a magnetic core member has one pole for carrying the charging winding and another pole for carrying a control winding. The charging winding serves to charge a capacitor which stores the ignition energy for firing the spark plug of the engine. A magnet mounted on a rotatable disc is moved past the poles of the core member and thereby induces voltages, in sequence, within the charging and control windings. The capacitor discharges through the primary winding of an ignition transformer, with the discharge controlled by a control rectifier. The control electrode of the rectifier is connected to the control winding of the magnetic core member. Upon discharge of the capacitor, an ignition pulse for firing the spark plugs is induced in the secondary winding of the ignition transformer.

United States Patent [54] IGNITION ARRANGMENT FOR INTERNAL COMBUSTIONENGINES l2 Claims,4 Drawing Figs.

[52] U.S.Cl 123/148 E, 123/41 E, 123/1465 A, 123/149 D [51] lnt. F02p3/06 [50] FieldolSeareh 123/1465, 148 E, 149, 149 D, 148AC,41E',310I10,153; 315/209 [56] References Cited UNITED STATES PATENTS3,447,521 6/1969 Piteo 123/148 3,484,677 12/1969 Piteo 123/148 X PrimaryExaminer-Laurence M. Goodridge Attorney-Michael S. Striker ABSTRACT: Anignition arrangement for internal combustion engines in which a magneticcore member has one pole for carrying the charging winding and anotherpole for carrying a control winding. The charging winding serves tocharge a capacitor which stores the ignition energy for firing the sparkplug of the engine. A magnet mounted on a rotatable disc is moved pastthe poles of the core member and thereby induces voltages, in sequence,within the charging and control windings. The capacitor dischargesthrough the primary winding of an ignition transformer, with thedischarge controlled by a control rectifier. The control electrode ofthe rectifier is connected to the control winding of the magnetic coremember. Upon discharge of the capacitor, an ignition pulse for firingthe spark plugs is induced in the secondary winding of the ignitiontransformer.

IGNITION ARRANGMENT FOR INTERNAL COMBUSTION ENGINES I BACKGROUND OF THEINV ENTION The present invention resides in an ignition arrangement forinternal combustion engines in which an ignition capacitor serves tostore the ignition energy. The capacitor is charged through a chargingcoil which has a voltage induced within it. The capacitor is dischargedwith the aid of a contactless controlled electronic switch, through theprimary winding of an ignition transformer. The secondary winding ofthis transformer is connected to at least one spark plug.

Such ignition arrangements are particularly adapted to operate in caseswhere a battery is not available as an energy source for supplying poweror feeding the ignition arrange ment. Furthermore, no mechanicalswitches with their accom panying disturbances or noise effects arerequired. A particular simple arrangement may be realized, in accordancewith the present invention, which also guards against operation of theignition arrangement in the wrong or incorrect rotational direction. Inaccordance with the present invention, a ferromagnetic core is providedin which one pole forms the charging armature by carrying a chargingwinding, and a second pole forms the control armature by carrying acontrol winding. Charging and control voltages are induced within thesewindings through a magnet which is driven by the internal combustionengine and is moved past the charging armature and the control armature.

SUMMARY OF THE INVENTION An ignition arrangement for internal combustionengines in which a ferromagnetic core is designed with a first polecarrying a charging winding, and a second pole carrying a controlwinding. A magnet is mounted upon a rotatable member driven from thecrank shaft of the engine. When the poles of the magnet on the rotatablemember are driven past the poles of the ferromagnetic core carrying thecharging and control windings, voltages are induced respectively withinthese windings. An air gap is maintained between the pole carrying thecontrol winding and the remainder of the ferromagnetic core, for thepurpose of magnetically isolating the pole with the control winding fromthe core proper. The voltage induced within the charging winding chargesa capacitor which stores the ignition energy. The capacitor becomesdischarged through a control rectifier which discharges the energy fromthe capacitor through the primary winding of an ignition transformer,when actuated by the control voltage induced within the control winding.With the discharge of the ignition capacitor in this manner, an ignitionvoltage pulse is induced within the secondary winding of the ignitiontransformer which is connected to one or more spark plugs. A safetymeans is provided whereby firing of the spark plug is prevented when therotatable member rotates in the wrong direction.

The novel features which are considered as characteristic for theinvention are set forth in particular in the appended claims. Theinvention itself, however, both as to its construction and its method ofoperation, together with additional objects and advantages thereof, willbe best understood from the following description of specificembodiments when read in connection with the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a functional and electricalcircuit diagram and FIG. 3 is a graphical representation of the inducedvoltages in the charging winding and control winding on theferromagnetic core of FIG. 1, when the rotatable member used forinducing these voltages rotates in the wrong direction; and

FIG. 4 is a further embodiment of the ignition arrangement, inaccordance with the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawing and inparticular to FIG. I, the ferromagnetic core I0 is designed in the formof three sections or members. The first pole II carries a charging coil12 on a charging armature. A second pole 13 designated as a controlarmature has wound upon it a control coil or winding 14. The middle orthird pole I5 carries the primary winding 16 and the secondary windingI7 of an ignition transformer. An air gap 28 between the pole I3 and theremaining portion of the ferromagnetic core 10 is provided for thepurpose of magnetically decoupling the control armature designated asthe third pole 13 from the remaining ferromagnetic core. In the vicinityor proximity of the ferromagnetic core 10, a disc 18 is rotatablymounted. The disc is driven through a coupling represented by thedash-dot lines to the internal combustion engine, not shown. A magnet 19is mounted at the external rim of the disc I8, so that the magneticpoles 20 and 21 of this magnet 19 are moved past the poles I1, I3 and I5of the ferromagnetic core I0. This magnet I9 is arranged on the disc I8so that the poles of this magnet move closely past these poles 11, I3and I5 as the disc is rotated.

On end or terminal of the control winding 14 on the pole I3 is connectedto ground potential, whereas the other end or terminal of this controlwinding 14 is connected to the anode or a diode 22. The cathode of thisdiode 22 is connected, in turn, to the control electrode of a thyristor23. The cathode of this thyristor 23 has ground potential applied to it,whereas the anode is connected to one end or terminal of the primarywinding 16 of the ignition transformer. The junction of the primarywinding 16 with the secondary winding I7 of the ignition transfon'ner isconnected to an ignition capacitor 24 and to the cathode of a chargingrectifier 25. The anode of this charging rectifier or diode 25 leads toground potential through the charging winding or coil I2. The otherelectrode of the capacitor 24 is also connected to ground potential. Aspark plug 26 is connected, with one terminal, to the secondary windingI6, whereas the other terminal of this spark plug has ground potentialapplied to it.

In operation of the ignition arrangement, the correct rotationaldirection for the disc 18 is shown in FIG. 2. With this rotationaldirection of the disc 18, a voltage is induced in the charging coil 12of the charging armature designated with the pole I]. A voltage is alsothen induced within the control winding 14. The induced voltages resultfrom the motion of the poles 20 and 21 of the magnet 19 past the polesII and 13. Thus, these voltages are induced through the cutting actionof the magnetic field of the magnet I9, produced as the latter movespast the poles II and 13, in sequence. The voltage induced within thecoil 12 is initiated when the disc 18 is in the position a. The functionof the induced voltage withinv the charging coil 12 and the control I4is designated in broken lines in FIG. 2. This voltage is of noconsequence for charging the ignition capacitor. There is, however, thedangerous possibility that this half-wave fires the thyristor andthereby prevent charging of the capacitor 24. For this reason, aferromagnetic member 27 is joined to the first pole II for the purposeof weakening the effect of the flux variation incurred when the magneticpoles 20 and 21 move past the pole II. The ferromagnetic member 27provides that the undesired or disturbing voltage is suppressed to asubstantially small residue, so that the function designated with solidlines in FIG. 2 is realized.

In the position b of the disc 18, the variation of the magnetic fluxlinking the charging coil 12, is maximum. As a result, the inducedcharging voltage U achieves, in this position of the disc 18, a maximumvalue or level. The charging voltage U is induced within the chargingcoil 12 as a result in the variation in the magnetic flux. Due to thecharging voltage U the ignition capacitor 24 becomes charged through thecharging diode or rectifier 25. When the disc 18 is in the positionbetween locations and d, a predetermined control voltage U is induced,and the thyristor 23 becomes fired at the firing or ignition instant 2?,when the induced control voltage has reached a predetermined level. Thecapacitor 24 then discharges through the primary winding 16 of theignition transformer. The high voltage induced, thereby, within thesecondary winding 17, produces a spark to cross the gap of the sparkplug 26.

The ignition arrangement of the present invention exhibits theparticular advantage that when the disc 18 rotates in the wrongdirection, the ignition arrangement does not provide sufficient ignitionvoltage. As a result, reverse operation of the engine is inhibited. Thisprocess is particularly clearly shown in FIG. 3.

When the disc 18 rotates in the wrong direction, the polarity of thecharging voltage U ,and the control voltage U is reversed. The capacitor24 would, thereby, become essentially charged through the half-waveproduced when the disc 18 is in the position c. Such charging of thecapacitor can, however, not take place, since the thyristor 23 ismaintained in the conducting state, at that instant, through the controlvoltage U The low charging voltage with which the ignition capacitor 24becomes charged when the disc in the position a, is at such a low leveldue to the presence of the ferromagnetic member 27, so that a sparkcannot appear across the electrodes of the spark plug 26.

The half-cycle of voltage produced at a is largely caused by themagnetic leakage flux present at this position. This voltage could causeso great a charge on capacitor 24 that the spark plug could produce ahot spark, despite the overlapping of the charging and control voltagesat position c. The member 27 partly short circuits the leakage flux andtherefore causes a lower induced voltage, as shown in full line in FIG.3. This lower voltage is too small to cause a hot spark.

A further advantage of the ignition arrangement, in accordance with thepresent invention, resides in the feature that the leading pulse edgesof the control voltage become steeper when the rotational speed of theengine and hence the disc 18 increases, provided that the engine isrotating in the correct direction. As a result of this condition, theswitching threshold of the thyristor is realized more rapidly betweenthe positions c and d/This feature or process has the effect ofadvancing the ignition instant and thereby increase the power output ofthe internal combustion engine.

The ferromagnetic core is designed, in the preceding embodiment, in theform of a three-pole core having a middle pole which carries theignition transformer. This ferromagnetic core 10 can also be designed inthe form of a core with two poles in which the ignition transformer isarranged or mounted in any desired position.

In the event that it is of advantage from the viewpoint of spaceconservation, the control armature can also be mounted within a disccoupled to the internal combustion engine. in such an arrangement, thedisc includes or contains a second permanent magnet with interior poles.

A particularly advantageous design and fabrication of the ignitionarrangement has been found from the viewpoint of low cost andsimplicity, when the pole carrying the control winding exhibits lowerstrength than the pole carrying the charging winding.

in another embodiment, in accordance with Fit). 4, the windings upon theferromagnetic core 10 are interchanged in their series connection. Thethree-member ferromagnetic core 10 carries upon its first pole II, theprimary winding 16, as well as the secondary winding 17 of the ignitiontrans former. The charging coil 12 is wound upon the second pole l5, andthe control armature designated as the third pole 13, carries thecontrol winding 14. For the purpose of decoupling magnetically the pole13 from the remaining ferromagnetic core, an air gap 28 is providedbetween the pole l3 and the remaining portion of the ferromagnetic core10, similar to that described in relation to the first embodiment. Sincethe necessary control voltage can also be considerably small in thisembodiment, the pole for the control armature will suffice with lessstrength than the remaining ferromagnetic core 10. The control armaturecan, in particular, be formed of individual laminations. Through suchconstruction, particular fabrication advantages and fabricationeconomies are realized. The disc 18 is rotatably mounted in theproximity of the ferromagnetic core 10. The disc is driven by theinternal combustion engine through a coupling shaft designated in thedrawing through a dash-dot line. The magnet 19 is arranged along theouter rim of the disc 18, and the poles 20 and 2! of the magnet 19 passclosely the poles of the ferromagnetic core 10 in the rotation of thedisc. The functional operation of this particular embodiment isbasically identical to that described in relation to the precedingembodiment. For the purpose of securing the safety feature againstreturn motion over the entire rotational region, the second embodimenthas, however, the ferromagnetic member 27 on the third pole instead ofthe first pole viewed from the direction of motion.

The purpose of the member 27 is to suppress undesired voltage pulses,arising from leakage flux, that could cause the spark plug to spark whenit should not.

An additional advantage is realized through this arrange ment of theferromagnetic core 10 in which the wound coils follow in series, in thedirection of motion, with the sequence of the ignition transformer 16and 17, the charging coil 12, and the control winding 14, in contrast tothe first embodiment. This advantage results from the condition that themaximum magnetic flux appearing at the center pole ll may be used forcharging the ignition capacitor. Through this feature, a relativelylarge charge may be achieved with a low number of turns in the chargingwinding.

The ignition arrangement as described above in relation to one sparkplug, can also be used in conjunction with installations or arrangementsusing a number or plurality of spark plugs. When using a larger numberof such spark plugs, the ignition voltage pulse may be applied to thespark plugs through an ignition distributor, as known in the art, andthe rotational speed of the disc i8 may, for example, be increased.

it is also possible, furthermore, to hold the disc 18 stationary and torotate the ferromagnetic core 10 instead.

The thyristor used in the embodiment, as described, can also be replacedthrough another electronic switch which consists of, for example,electronic vacuum tubes or semiconductor elements in the form oftransistors or diodes.

For particular applications, the electrical circuit and/or the woundferromagnetic core may be embedded within a plastic mass board aroundthem in a process known in the art as potting. in a particularadvantageous design, the electronic components of the circuit aremounted on a hard fiber board secured to the ferromagnetic core 10.

It will be understood that each of the elements described above, or twoor more together, may also find a useful application in other types ofconstruction differing from the types described above.

While the invention has been illustrated and described as embodied in anignition arrangement for internal combustion engines, it is not intendedto be limited to the details shown, since various modifications andstructural changes may be made without departing in any way from thespirit of the present invention.

What we claim as new and desired to be protected by Letters Patent isset forth in the appended claims:

1. An ignition arrangement for internal combustion engines comprising,in combination, a magnetic core member with first and second spacedpoles; a charging winding carried by said first pole; a control windingcarried by said second pole; magnetic means linked drivenly to saidinternal combustion engine and driven past said first and said secondpoles in turn,

winding; transformer means having primary and secondary windings;electronic switching means controlled by said control voltage induced insaid control winding for discharging said capacitor means through saidprimary winding of said transformer means, said magnetic means andcharging and control windings being arranged so that said chargingvoltage induced in said charging winding occurs before said controlvoltage induced in said control winding when the engine rotates in thedesired direction and so that said charging and control voltage overlapwhen the engine rotates in opposite direction, whereby an ignitioncausing pulse for at least one spark plug is induced in said secondarywinding only w ten the engine rotates in said desired direction.

2. The ignition arrangement as defined in claim 1, wherein said magneticcore member includes a third pole.

3. The ignition arrangement as defined in claim 2, including a rotatabledisc for supporting said magnetic means, said transformer means beingmounted on said third pole, so that in the desired direction of rotationof the engine said magnetic means moves past said first pole, saidsecond pole next, and finally said third pole.

4. The ignition arrangement as defined in claim l, wherein said magneticcore member includes an auxiliary pole for carrying said transformermeans, and further including rotatable disc means, rotated by theengine, for supporting said magnetic means, said magnetic means, whenthe engine rotates in the desired direction, successively moving pastthe pole carrying said transformer means, the pole carrying saidcharging winding, and the pole carrying said control winding.

S. The ignition arrangement as defined in claim 1 including armaturemeans spaced from said magnetic core member for carrying saidtransformer means.

6. The ignition arrangement as defined in claim 1 wherein said secondpole carrying said control winding is spaced from the remaining portionof said magnetic core member through an air gap.

7. The ignition arrangement as defined in claim I wherein the polecarrying said control winding has a lower amount of magnetic flux thanthe pole carrying said charging winding.

8. The ignition arrangement as defined in claim 1 wherein said polecarrying said control winding is comprised of individual laminations.

9. The ignition arrangement as defined in claim 1 including hard fiberboard means carried by said magnetic core member and said capacitormeans, transformer means and electronic switching means being arrangedon said hard fiber board means.

10. The ignition arrangement as defined in claim I including plasticmeans for embedding said magnetic core member, said capacitor means,said transformer means and electronic switching means.

'1 l. The ignition arrangement as defined in claim 1 includingferromagnetic means upon said pole carrying said charging winding forreducing the amplitude of undesired pulses induced in said chargingwinding.

12. The ignition arrangement as defined in claim 4 includingferromagnetic means on said pole carrying said control winding forsuppressing undesired voltage pulses arising from leakage flux thatcould cause unintentional sparking of the spark plug.

1. An ignition arrangement for internal combustion engines comprising,in combination, a magnetic core member with first and second spacedpoles; a charging winding carried by said first pole; a control windingcarried by said second pole; magnetic means linked drivenly to saidinternal combustion engine and driven past said first and said secondpoles in turn, whereby a charging voltage is induced in said chargingwinding and a control voltage is induced in said control winding;capacitor means for storing the ignition energy and adapted to becharged by said charging voltage induced in said charging winding;transformer means having primary and secondary windings; electronicswitching means controlled by said control voltage induced in saidcontrol winding for discharging said capacitor means through saidprimary winding of said transformer means, said magnetic means andcharging and control windings being arranged so that said chargingvoltage induced in said charging winding occurs before said controlvoltage induced in said control winding when the engine rotates in thedesired direction and so that said charging and control voltages overlapwhen the engine rotates in opposite direction, whereby an ignitioncausing pulse for at least one spark plug is induced in said secondarywinding only when the engine rotates in said desired direction.
 2. Theignition arrangement as defined in claim 1, wherein said magnetic coremember includes a third pole.
 3. The ignition arrangement as defined inclaim 2, including a rotatable disc for supporting said magnetic means,said transformer means being mounted on said third pole, so that in thedesired direction of rotation of the engine said magnetic means movespast said first pole, said second pole next, and finally said thirdpole.
 4. The ignition arrangement as defined in claim 1, wherein saidmagnetic core member includes an auxiliary pole for carrying saidtransformer means, and further including rotatable disc means, rotatedby the engine, for supporting said magnetic means, said magnetic means,when the engine rotates in the desired direction, successively movingpast the pole carrying said transformer means, the pole carrying saidcharging winding, and the pole carrying said control winding.
 5. Theignition arrangement as defined in claim 1 including armature meansspaced frOm said magnetic core member for carrying said transformermeans.
 6. The ignition arrangement as defined in claim 1 wherein saidsecond pole carrying said control winding is spaced from the remainingportion of said magnetic core member through an air gap.
 7. The ignitionarrangement as defined in claim 1 wherein the pole carrying said controlwinding has a lower amount of magnetic flux than the pole carrying saidcharging winding.
 8. The ignition arrangement as defined in claim 1wherein said pole carrying said control winding is comprised ofindividual laminations.
 9. The ignition arrangement as defined in claim1 including hard fiber board means carried by said magnetic core memberand said capacitor means, transformer means and electronic switchingmeans being arranged on said hard fiber board means.
 10. The ignitionarrangement as defined in claim 1 including plastic means for embeddingsaid magnetic core member, said capacitor means, said transformer meansand electronic switching means.
 11. The ignition arrangement as definedin claim 1 including ferromagnetic means upon said pole carrying saidcharging winding for reducing the amplitude of undesired pulses inducedin said charging winding.
 12. The ignition arrangement as defined inclaim 4 including ferromagnetic means on said pole carrying said controlwinding for suppressing undesired voltage pulses arising from leakageflux that could cause unintentional sparking of the spark plug.